Synthesis and in vitro anti-arthritic,anti-inflammatory studies on hypervalent pyranoside glycodendrimers with triazole bridging point

Synthesis of novel glycodendrimer scaffolds containing hypervalent sugar pyranosides and triazole bridging points is described. Dendrimers with a greater number of bridging triazole units and α-d-glycopyranosyl surface groups exhibit better anti-arthritic and anti-inflammatory activity than dendrimers with less number of triazole and α-d-glycopyranosyl units.     

Synthesis and Characterization of Some Novel Glycodendrimers and N-alkyldendrimers with Amide Core and Triazole Functionality through Click Chemistry

The syntheses of various types of 1,2,3-triazole-based dendrimers 1–4 with sugar pyranosylazides and N-ethyl and N-heptylazides as a surface unit and benzene-1,3,5-tricorboxlyic amide as core unit through click chemistry approach are described.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Pyrolysis-controlled synthesis and magnetic properties of sol–gel electrospun nickel cobaltite nanostructures

Poly(chloropropyl-methyl)silsesquioxanes (PCMSQ) were prepared using the base catalyzed sol–gel processing on methyltrimethoxysilane (MTMS) and 3-chloropropyltriethoxysilane (CPTES) with 5:5, 6:4, and 7:3 molar ratios in methanol and water. The PCMSQ with 6:4 molar ratio of MTMS:CPTES, which has the maximum yield, according to the elemental analysis, was chosen and some chlorine atoms of the chloropropyl groups were changed to different amines by refluxing it with ethylenediamine (en), diethylenetriamine (dien), ortho-phenylenediamine (opda), and 2-imidazolidinethion (imt). The amine grafted PCMSQ were then used to support MoO₂(acac)₂ complex and dien grafted PCMSQ with higher metal content was applied to the epoxidation of cis-cyclooctene with TBHP. The product yields were studied by gas liquid chromatography and the catalytic procedure was optimized for the parameters involved such as the solvent and oxidant. The catalytic activity of this catalyst also was investigated toward epoxidation of some other alkenes. It was also applied to check its reuse ability.

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In this research, micro-spherical poly-organo-silsesquioxane was prepared using the base catalyzed sol–gel processing of methyltrimethoxysilane and 3-chloropropyltriethoxysilane with different molar ratios. The sample which has the maximum yield, was used to graft MoO₂(acac)₂ and for the successful anchoring, some chlorine atoms of the chloropropyl side groups were changed to amines. Then the prepared catalyst with higher molybdenum content was used for the epoxidation of cis-cyclooctene and some other alkenes with TBHP.

     

Radon isotope assessment of submarine groundwater discharge (SGD) in Coleroon River Estuary,Tamil Nadu,India

Submarine groundwater discharge is the fresh groundwater discharge to sea that impacts the coastal regions. Radon (²²²Rn) isotope has been used to quantify SGD in coleroon river estuary, India. Continuous ²²²Rn analyses were attempted for 10 days in groundwater and pore water samples at three different locations. ²²²Rn in groundwater ranges between 35.0 and 222.0 Bq m^?3 and in pore water between 14.0 and 150.0 Bq m^?3 irrespective of locations. The radon mass balance estimated total SGD rate ranges between 2.37 and 7.47 m days^?1. The SGD increases with distance from coast, influenced by tides and hydrological features.     

Chemical diversity and anti-proliferative activity of marine algae

The chemical diversity of three macroalgae (Ulva reticulata, Sargassum wightii, Gracilaria sp) were determined using the GC-MS method with principal component analysis (PCA) and their potential efficacy against human pathogens and cervical carcinoma cells evaluated using MTT bioassay method. Our results showed that >30 metabolites were detected in three seaweeds, among these, steroids and fatty acids are the most dominant chemical group that highly contributes to discriminate this species. The PCA of GC-MS mass spectral variables showed a clear discrimination between three different species based on the phytochemical diversity of seaweeds. The extracts of U. reticulata exhibited anti-microbial activity with Pseudomonas aeruginosa (6.00?mm) and showed potential anti-proliferative activity against the HeLa cells (IC₅₀ 37?µmol/L) at concentration 1–50?µM treatment. Results of this study concluded that PCA analysis of mass spectral variables could be utilized as a reliable tool for species discrimination and chemotaxonomic classification of seaweeds.     

Reply to the Letter-to-the-Editor of Dr. Noble Jacob regarding article “Radon isotope assessment of Submarine Groundwater Discharge (SGD) in Coleroon River Estuary,Tamil Nadu,India”, DOI: https://doi.org/10.1007/s10967-018-5877-2

Journal of Radioanalytical and Nuclear Chemistry -     

Structural characterization of nano-crystalline Co3O4 ultra-fine fibers obtained by sol–gel electrospinning

In this paper, we report the obtention of ultrafine fibers of cobalt oxide (Co₃O₄) by combining electrospinning method with high-temperature calcinations from the precursor sol of poly(2-ethyl-2-oxazoline) (PEtOx)/cobalt acetate tetrahydrate [Co(CH₃COO)₂·4H₂O] in water. The optimum electrospinning conditions for obtaining precursor composite nanofibers from PEtOx/Co(CH₃COO)₂·4H₂O solution in water, to produce ceramic nanofibers, were studied. The average fiber diameter of the precursor composite fibers measured by scanning electron microscopy (SEM) was approximately 200 nm. Thermogravimetric analysis of PEtOx was performed to estimate the suitable calcination temperature of the precursor fibers. SEM images of the ceramic fibers obtained after calcination revealed the shrinkage in diameter due to complete degradation of the polymer and Co(CH₃COO)₂·4H₂O. Fourier transform infrared spectroscopy was used to ensure the complete pyrolysis of polymer during calcinations of the composite fibers. Crystalline properties of the ceramic fibers were studied by X-ray diffraction and high resolution transmission electron microscopy. The ceramic fibers are polycrystalline with an average grain size of ≈40 nm obtained at a calcination temperature of 773 K. It was observed that the grain sizes increased as the calcination temperature was increased, due to self assembly mechanism.     

Enhanced sensing of anthraquinone dyes using multiwalled carbon nanotubes modified electrode

The voltammetric behaviour of two anthraquinone dyes such as Alizarin Red S (ARS) and Reactive blue 4 (RB4) was investigated at plain glassy carbon electrode (GCE), multiwalled carbon nano tube modified GCE (MWCNT/GCE) and zeolite modified GCE (ZE/GCE) using cyclic voltammetry. Effects of pH, scan rate and concentration were studied. The surface morphology of the modified electrode in the absence and presence of dye molecules was characterized by scanning electron microscopy (SEM). A systematic study on the variation of experimental parameters with differential pulse stripping voltammetry (DPSV) was carried out and the optimized experimental conditions were arrived. MWCNT/GCE performed well among the three electrode systems and the limit of detection (LOD) was 0.036?µg?mL^?1 for ARS and 0.05?µg?mL^?1 for RB4 on this modified system. Suitability of the differential pulse stripping voltammetric method for the trace determination of textile dyes in effluents was also realized.     

Synthesis and optical and electrochemical properties of glucose-cored ferrocenyl dendrimers

Triazole-based ferrocenyl glycoconjugates 1, 2, and 3 were synthesized by regiospecific copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) of azidoferrocenyl derivatives with glucose pentaacetylide. Higher generation ferrocenyl glycoconjugates form the stable ferrocenium cation and exhibit increased light harvesting property as revealed from cyclic voltammogram studies and ultraviolet–visible spectrum respectively due to the presence of more ferrocenyl and triazolyl units than the lower generation dendrimer.